1. Field of the Invention
The present disclosure relates to an organic light emitting display device, and, more particularly, to an organic light emitting display device improving light emitting efficiency by reducing an amount of light that dissipates while the light generated from an emission layer is discharged to the outside environment.
2. Description of the Related Art
An organic light emitting display device is a self-emission display device which has an organic light emitting diode that emits light to display an image. Since the organic light emitting display device has characteristics such as low power consumption, high luminance, and a high response speed, the organic light emitting display device currently receives attention as a display device.
In general, in the organic light emitting display device, a portion of the device generating light is called a display unit, and the display unit includes a hole injection electrode, an emission layer, and an electron injection electrode. In the organic light emitting display device, holes supplied from the hole injection electrode and electrons supplied from the electron injection electrode are coupled with each other in the emission layer to generate light. Generally, the hole injection electrode is an anode, and the electron injection electrode is a cathode.
However, the display unit can be easily damaged by an external gas such as oxygen or moisture, and the display unit may deteriorate due to contact with oxygen or moisture. Accordingly, in order to prevent oxygen or moisture from penetrating from the outside, an encapsulation structure for sealing and protecting the display unit is required.
As an example of such an encapsulation structure, an encapsulation layer, specifically a thin film encapsulation layer, in which inorganic layers and organic layers are alternately laminated is adopted. That is, the encapsulation layer, in which inorganic layers and organic layers are alternately laminated, is formed on the display unit, which is formed on a substrate to seal the display unit and thus protect the display unit. Here, the organic layer mainly functions to give flexibility to a flat panel display, and the inorganic layer mainly serves to prevent oxygen or moisture from penetrating into the device.
However, when the light generated from the emission layer is discharged to the outside environment, a large amount of light dissipates while passing through a laminated structure such as the encapsulation layer disposed on the emission layer. The light efficiency of the organic light emitting display device is not good because the light dissipates. Accordingly, in order to increase the light efficiency in the organic light emitting display device, dissipation of the light needs to be minimized.